Our objectives are to analyze the mechanisms by which lymphocytes sensitized in vitro prevent tumor growth in vivo; and to evaluate the immunotherapeutic potential of such cells for transplanted and primary tumors. During the coming year, we will emphasize studies to define the association of viral antigens and cell-mediated immune responses to a rat virus-induced syngeneic lymphoma and define the subsets of T-cells responsible for elimination of tumor cells in vivo using a mouse syngeneic lymphoma. The extent to which prevention of tumor growth involves participation of host cells recruited by transferred activated lymphoid cells will be assessed. The presence of cellular or humoral factors present in tumor bearing animals which potentially can interfere with the activity of these cells will also be determined. We will also study the antigens associated with generation and expression of antitumor activity and the role of immunoadjuvants such as BCG on the generation of specific anti-tumor responses. These studies may allow for a better understanding of host cellular immune mechanisms which mediate rejection of neoplastic cells and an improved approach to the passive cellular immunotherapy of tumors.